This invention relates to clamp fixtures of the type used in association with pipe clamps and bar clamps, and more particularly to clamping systems which are easily reconfigurable to facilitate use of any of various different clamping fixtures which are specially adapted for clamping certain types of workpieces or other articles.
Pipe clamp assemblies and bar clamp assemblies, hereinafter collectively referred to as beam clamp assemblies, are commonly used to hold workpieces or other articles in a fixed position for various operations such as cutting, drilling, nailing, screwing, gluing, etc. Beam clamp assemblies generally comprise a linear beam (e.g., a pipe, rod or bar), and a pair of opposing jaws, at least one of which is slidably supported on the beam. A first of the jaws is either fixed to one end of the beam or includes a locking device for holding the jaw in a selected position on the beam. A linear actuator is provided to linearly advance the second jaw toward and away from the first jaw to apply and relieve pressure on an article interposed between the jaws. Typically, the jaws of beam clamp assemblies have parallel opposing gripping surfaces. Accordingly, beam clamp assemblies are generally adapted for clamping workpieces or other articles having flat, parallel opposing surfaces. However, in order to clamp a variety of articles or workpieces at nonplanar surfaces or surfaces which are not parallel to the gripping surface of the jaws, specially designed fixtures or jigs are generally utilized. For example, to grip the corner of a picture frame, specially configured miter jigs having mitered gripping surfaces have been designed. These specialty jigs have been provided with integral fasteners, such as sockets or clips, to allow attachment of the jigs to the jaws of the beam clamp assembly. A disadvantage with conventional jigs is that they are designed for attachment to a particular type or model of beam clamp assembly and cannot be used interchangeably with beam clamp assemblies having jaw gripping surfaces of a size or shape which is not suitably configured to cooperatively receive the integral fasteners on the jigs. This lack of interchangability can be a disadvantage and inconvenience to workers who must match the jig for a particular job to a specific type of beam clamp assembly which may, for example, be unavailable because it is being used for another job.
It is desirable that jigs or fixtures used for clamping a particular type of workpiece or article be firmly secured to the jaws of the beam clamp assembly to prevent shifting of the fixtures relative to the workpiece or article during clamping and subsequent operations. As a result, the dimensional tolerances between the jaws and the integral fasteners on the jigs are extremely low. Consequently, another disadvantage with conventional clamping fixtures is that installation of the fixtures onto the jaws and removal of the fixtures from the jaws can be relatively difficult and time consuming.
When a beam clamp assembly is used without a special fixture or jig, such as to clamp an article or workpiece having opposing parallel, planar surfaces, it is generally desirable to provide a protective layer between the gripping surfaces of the jaws and the gripped surfaces of the article or workpiece being clamped, to prevent abrasion of the surface of the clamped article or workpiece by irregularities, such as bumps and protuberances, which are generally inherently formed during casting of steel jaws. For this purpose, rubber clamp pads which can be slipped over the gripping surfaces of the jaws have been provided. While conventional clamping pads provide some protection against abrasion, there are several disadvantages associated with their use. Included among the disadvantages of conventional rubber, slip-on clamping pads is that because of the flexibility and deformability of the rubber pads, true clamping pressure between the jaws and the workpiece is not achieved, and the rubber pads can tend to slip or shift relative to the jaws during clamping or subsequent operations on a workpiece being clamped. Another disadvantage with conventional beam clamping systems and rubber clamping pads is that the rubber clamping pads must be removed when a specialty clamping fixture is used, and replaced when it is desired to again use the beam clamp assembly to clamp a workpiece having parallel, planar opposing surfaces. Thus, reconfiguring a beam clamp assembly between a configuration in which a specialty jig is used and one in which clamping pads are used can be difficult and time consuming.
This invention provides adaptors for interchangeably connecting any of a plurality of clamping fixtures to various beam clamp assemblies. The adaptors of this invention are each configured to be mounted onto a particular type of beam clamp assembly, and each adaptor is provided with a connector for releasably attaching any of a plurality of clamping fixtures to the adaptors, whereby a particular clamping fixture can be interchangeably mounted on any of a plurality of different types of beam clamp assemblies, thus eliminating the need to match the clamping fixture for a particular job to a particular type of beam clamp assembly.
The adaptors in accordance with this invention include an adaptor block or body, a fastener attached to the adaptor block for releasably securing the adaptor block to a jaw of a beam clamp assembly, and a connector on the adaptor block for releasably attaching a workpiece clamping fixture to the adaptor block.
In accordance with one aspect of the invention, there is provided a clamping system for clamping workpieces for various operations. The system includes a beam clamp assembly, or a plurality of different types of beam clamp assemblies, each of which may have jaws which are differently configured; an adaptor having a fastener specially configured to facilitate releasable attachment to the jaws of the beam clamp assembly, or a plurality of adaptors, each having a fastener specially configured to facilitate releasable attachment to one of the plurality of different types of beam clamp assemblies having differently configured jaws, each of the adaptors including a connector for releasably attaching a workpiece clamping fixture to the adaptor; and one or more workpiece clamping fixtures, each clamping fixture including a connector configured to engage the connector on any of the adaptors and facilitate releasable attachment of the clamping fixture to any of the adaptors. The clamping system of this invention thus allows a workpiece clamping fixture to be mounted onto, and to be used with, any of a plurality of different beam clamp assemblies having differently configured jaws. By providing a clamping system which allows any of a plurality of different types of workpiece clamping fixtures to be used with any of a plurality of different types of beam clamp assemblies having differently configured jaws, greater flexibility in the selection of clamping fixtures and beam clamp assemblies for performing a particular job on a particular workpiece is provided. More specifically, workers are not limited by the requirement of having to utilize a particular workpiece clamping fixture with a particular type of bar clamp assembly having jaws which are configured to cooperatively receive integral fasteners on the workpiece clamping fixture.
In accordance with another aspect of the invention, the adaptor includes a workpiece-engaging surface which faces toward an opposing second jaw of the beam clamp assembly when the adaptor is secured to a first jaw of the beam clamp assembly. The workpiece-engaging surface allows the adaptor to be used as a clamp pad when a workpiece fixture is not mounted on the adaptor. This feature eliminates the need for replacing the workpiece fixture with a protective clamp pad when the beam clamp assembly is reconfigured from being used with a specialty workpiece fixture to being used to clamp a workpiece having opposing parallel, planar surfaces which are to be gripped between the jaws of the beam clamp assembly. Accordingly, the difficult tasks of mounting the workpiece fixtures onto the jaws and demounting the workpiece fixtures from the jaws during reconfiguration is eliminated. Such tasks being difficult and time consuming on account of the extremely low tolerances between the jaws and the integral fasteners on conventional clamping fixtures. Instead, in accordance with this aspect of the invention, the adaptors are firmly secured to the jaws and do not need to be removed during reconfiguration of the beam clamp assembly between a configuration in which a specialty clamping fixture is utilized and one in which flat, parallel surfaces of a workpiece are to be gripped between the jaws, because the adaptors are provided with integral opposing gripping surfaces which generally serve the protective function of conventional clamping pads. Further, instead of detaching the clamping fixture from the jaw, as is required with conventional clamping systems, the clamping fixtures of the present invention are detachable from the adaptors for reconfiguration of the beam clamp assembly. In accordance with a preferred aspect of this invention, detachment of a clamping fixture from an adaptor can be a relatively simple task, which can be facilitated with a threaded fastener, with a snap-type connector, or with any of various other connectors which facilitate quick connection of the fixture to the adaptor and quick detachment of the fixture from the adaptor.
In accordance with a further aspect of the invention, there is provided a clamping fixture including a clamping body defining workpiece-engaging surfaces, and an adaptor portion which is integrally connected to, or integrally formed with, the clamping body. The adaptor portion includes first and second fastener clips for releasably securing the clamping fixture to one of the jaws of a beam clamp assembly. The clips are adjustable to allow variation of gripping forces with which the adaptor portion engages the jaw, so that the clips can be loosened to allow the adaptor portion to be easily mounted onto and removed from the jaw, and tighten to allow firm securement of the adaptor portion on the jaw. However, it will usually be unnecessary to loosen the clips. Instead, the fixture can be removed and replaced by sliding it onto or off of the jaws of the clamp assembly. In accordance with a preferred aspect of the invention, the clips are fastened to the adaptor portion with threaded fasteners, so that the clips can be removed from the adaptor portion and replaced with different clips which may be configured to engage the jaws of a different type of beam clamp assembly. Alternatively, the clips can be removed and used with different adaptors configured to be mounted on a differently configured jaw of a beam clamp assembly.
In accordance with another preferred aspect of the invention, the integral gripping surfaces of the adaptors can be made of a material which is relatively inflexible and relatively non-deformable as compared with rubber, so that true clamping pressure is achieved between the jaws and the workpiece. Also, because the gripping surface is integral to the adaptor, and because the adaptor includes fasteners for firmly securing the adaptor to the jaws of a beam clamp assembly, the possibility of the gripping surface or adaptor slipping or shifting relative to the jaws during clamping or subsequent operations on a workpiece is eliminated.